The key to a perfect baked chicken breast is temperature and timing. Chicken breasts are naturally lean, so if you overcook them they will come.
It could be that cooking at such a high temperature 'sears' the chicken to keep the juices inside, or it could be that the chicken breast bakes in.
I have tested cooking chicken breasts at different temperatures, ranging from 350 to 450 degrees F, and everything in between.
The secret to baking juicy chicken breast in the oven? Bake for a short time at a high temperature. 15-20 minutes at 450°F is perfect!.
Last, but by no means least, there is the temperature that your chicken should be cooked to for quality purposes—so that the breast meat is firm.